I subscribed to SlideBazaar a few months back and I can say firsthand that the templates are superb. Their after sales support is super nice as well.
Looka - Make a logo you’ll love with Looka Logo Maker.
SlideModel.com - Create attractive presentations with our professional PowerPoint templates, slide designs, and themes. Use our PPT templates and slide designs to give unique appearance to your presentation.
Logo Foundry - Logo Foundry is a professional Logo Design Suite App for Android and iOS that let's you create professional branding for your business in Minutes.
Slidesgo - An extensive catalog of free Google Slides themes and PowerPoint templates.
LogoMakr - Create & design your logo for free using an easy logo maker tool. Choose from hundreds of fonts and icons. Then just save your new logo on to your computer! Watch our video tutorial on how to create your logo.
SlideTeam - Transform rough sketches, notes into professional PowerPoint presentations.